President Obama speaks in the James Brady Press Briefing Room at the White House in Washington March 17, 2014. Obama on Thursday, Mar. 27, formally released his proposal to overhaul the NSA's metadata program.

Details of the plan appear unchanged from those leaked to the press earlier in the week. The White House draft legislation would replace part of the NSA’s dragnet with a more limited effort under which communications firms would retain “metadata” phone call info for 18 months, as they are already required to do by federal business regulations.

US spy agencies would have to get the approval of the secret Federal Intelligence Surveillance Court every time they wanted to search this data for a particular phone number, according to the White House. Their suspicions could be linked to general national security concerns, not counter-terrorism specifically.

They would then be able to further look at phone data out “two hops.” In other words, the NSA could investigate a suspicious first number, all numbers called or received by that first number, and then all numbers called or received by the second layer of numbers.

“The government’s handling of any records it acquires will be governed by minimization procedures approved by the [Federal Intelligence Surveillance Court],” said a White House fact sheet on the proposed program.

So why has the White House produced these changes now, nearly a year after NSA leaker Edward Snowden revealed the extent of the metadata program in the Guardian and the Washington Post?

From a practical point of view, the administration and the NSA are facing an upcoming legislative deadline. The part of the Patriot Act that authorizes the program, Section 215, is facing reauthorization. As White House documents on the proposal note, Obama had asked Attorney General Eric Holder and the US intelligence community to provide him with a workable plan “before the program comes up for reauthorization by the FISC on March 28th.”

This is why the White House proposal isn’t the only draft bill on the table. House Intelligence Committee chairman Rep. Ed Rogers (R) of Michigan and ranking minority member Rep. “Dutch” Ruppersberger (D) of Maryland have developed a competing plan that would allow the NSA somewhat more legal leeway about asking communications firms for data on particular numbers.

And any legislation on this question has to pass through the House Intelligence panel, as the Guardian reports. That gives Reps. Rogers and Ruppersberger a lot of leverage over the upcoming process.

Obviously, no bill on this subject will make it through Congress by March 28. Thus Obama is calling for a 90-day extension of the current program to cover the interim.

Obama has also made clear that he feels a need to do something to the NSA program to try and win back public trust lost by the Snowden leaks.

The implication of Obama’s proposal is that the White House appears to believe that there is nothing wrong with the current program from a legal and intelligence-gathering perspective. It is the very exposure of the scope of the effort to the light of day that may have caused most of the problem.

In a statement issued Thursday Obama says he is making his proposals “to give the public greater confidence that their privacy is appropriately protected, while maintaining the tools our intelligence and law enforcement agencies need to keep us safe.”

National security journalist and NSA expert Marcy Wheeler, a critic of the US surveillance network, writes Thursday that the Obama proposal is better than the House Intelligence Committee effort and “an improvement over the status quo.”

Ms. Wheeler does note that both plans would require communications firms to tailor their metadata records to provide the intelligence community what it needs – something they don’t do at the moment.

“In other words, these ‘reforms’ seem to arise as much from the fact that the outrage against this dragnet provides the government with an opportunity to build a system more appropriate to the task at hand rather than what they could jerry-rig together in secret,” Wheeler writes in her initial reaction to Thursday’s White House proposal.